Genetic basis of individual differences in the response to small-molecule drugs in yeast

Individual response to small-molecule drugs is variable; a drug that provides a cure for some may confer no therapeutic benefit or trigger an adverse reaction in others. To begin to understand such differences systematically, we treated 104 genotyped segregants from a cross between two yeast strains with a collection of 100 diverse small molecules. We used linkage analysis to identify 124 distinct linkages between genetic markers and response to 83 compounds. The linked markers clustered at eight genomic locations, or quantitative-trait locus 'hotspots', that contain one or more polymorphisms that affect response to multiple small molecules. We also experimentally verified that a deficiency in leucine biosynthesis caused by a deletion of LEU2 underlies sensitivity to niguldipine, which is structurally related to therapeutic calcium channel blockers, and that a natural coding-region polymorphism in the inorganic phosphate transporter PHO84 underlies sensitivity to two polychlorinated phenols that uncouple oxidative phosphorylation. Our results provide a step toward a systematic understanding of small-molecule drug action in genetically distinct individuals.     

Volatility Forecasting via MIDAS,HAR and their Combination: An Empirical Comparative Study for IBOVESPA

In this paper we compare several multi‐period volatility forecasting models, specifically from MIDAS and HAR families. We perform our comparisons in terms of out‐of‐sample volatility forecasting accuracy. We also consider combinations of the models' forecasts. Using intra‐daily returns of the BOVESPA index, we calculate volatility measures such as realized variance, realized power variation and realized bipower variation to be used as regressors in both models. Further, we use a nonparametric procedure for separately measuring the continuous sample path variation and the discontinuous jump part of the quadratic variation process. Thus MIDAS and HAR specifications with the continuous sample path and jump variability measures as separate regressors are estimated. Our results in terms of mean squared error suggest that regressors involving volatility measures which are robust to jumps (i.e. realized bipower variation and realized power variation) are better at forecasting future volatility. However, we find that, in general, the forecasts based on these regressors are not statistically different from those based on realized variance (the benchmark regressor). Moreover, we find that, in general, the relative forecasting performances of the three approaches (i.e. MIDAS, HAR and forecast combinations) are statistically equivalent. Copyright © 2014 John Wiley & Sons, Ltd.     

Brown-headed Cowbird parasitism on endangered species: relationships with neighboring avian species

Loss of reproductive productivity in hosts of the Brown-headed Cowbird ( Molothrus ater ), a nest parasite, may limit the success of conservation and recovery efforts that focus on restoring avian habitat. We investigated the relationships between parasitism frequency of 2 vireos—the endangered Black-capped Vireo ( Vireo atricapillus ) and the White-eyed Vireo ( Vireo griseus )—and characteristics of the neighboring avian assemblage. Our objective was to identify assemblage characteristics that are useful for predicting parasitism frequency. We hypothesized that parasitism frequency of the vireos would decrease with increasing alternate host abundance and increase with increasing abundance of cowbirds. All Black-capped Vireo nests ( n = 20) and 81% of White-eyed Vireo nests ( n = 27) were parasitized. Parasitism frequency of White-eyed Vireos was positively correlated with the number of cowbirds detected ( r = 0.84, df = 4, P = 0.018). Parasitism frequency of White-eyed Vireos was negatively correlated with abundance of the Black-and white Warbler ( Mniotilta varia; r = 0.891, df = 4, P = 0.009) but was not correlated with abundance of other cowbird hosts. The relationship between Black-and-white Warbler abundance and parasitism frequency may be due to chance, given the small sample size and narrow range of parasitism frequencies, but the relationship may also reflect an interaction (requiring further investigation) between parasitism and the vegetation characteristics associated with Black-and white Warblers. Our results imply that reducing cowbird abundance will reduce parasitism frequency of Black-capped Vireos. When the number of cowbirds in an area predicts parasitism, land managers would benefit from identifying a target cowbird abundance based on the levels of parasitism the host population can tolerate while still meeting productivity and population objectives for the species. La disminución de productividad debido al parasitismo por el tordo negro ( Molothrus ater ) podría limitar el éxito de los esfuerzos de conservación y recuperación de las aves que se centran en la restauración del hábitat. Investigamos la relación entre la frecuencia de parasitismo en el vireo gorrinegro ( Vireo atricapilla ), que está en peligro de extinción, y en otra especie de vireo, el vireo ojiblanco ( Vireo griseus ), así como su relación con las características de la población circunvecina de aves para identificar las características que sirven para predecir la frecuencia del parasitismo. Planteamos la hipótesis de que la frecuencia de parasitismo en los vireos disminuiría con el aumento de la abundancia de huéspedes alternativos y aumentaría al incrementarse la abundancia de tordos. Todos los nidos del vireo gorrinegro ( n = 20) y el 81% de los nidos del vireo ojiblanco ( n = 27) fueron parasitados. La frecuencia de parasitismo en los vireos ojiblancos estaba correlacionada positivamente con el número de tordos detectados ( r = 0.84, gdl = 4, P = 0.018). Estaba correlacionada negativamente con la abundancia ( r = 0.891, gdl = 4, P = 0.009) del chipe trepador ( Mniotilta varia ), pero no estaba correlacionada con la abundancia de otros huéspedes de los tordos. La relación entre la abundancia de chipe trepador y la frecuencia da parasitismo podría ser aleatoria, dado lo pequeño de la muestra y la poca variación en las frecuencias de parasitismo, pero también podría reflejar una interacción entre el parasitismo y las características de la vegetación asociada con el chipe trepador que requiere más investigación. Nuestros resultados indican que la disminución de la abundancia de tordos reduce la frecuencia de parasitismo en el vireo gorrinegro. Cuando el número de tordos en una área predice el parasitismo, los administradores de recursos naturales podrían beneficiarse de la identificación de una abundancia meta del tordo, basada en los niveles de parasitismo que la población huésped pueda sostener y todavía alcanzar los objetivos de productividad y población de la especie.     

Dynamics of rodent populations in semiarid habitats in Lassen County, California

From 1996 to 2004, we studied population dynamics of a rodent assemblage in semiarid habitats in Lassen County, California. Abundances of rodents appeared affected by fluctuations in precipitation from a high in 1996 to average and slightly below-average levels in subsequent years; perhaps reflecting this, assemblage composition also changed dramatically during the study period. California kangaroo rats ( Dipodomys californicus ) declined from abundant to extremely rare, abundances of deer mice ( Peromyscus maniculatus ) fluctuated greatly during the study period, and, perhaps most notably, populations of dusky-footed woodrats ( Neotoma fuscipes ) appeared to decline to local extinction, possibly allowing for the subsequent colonization of desert woodrats ( N. lepida ). These changes appeared to represent natural variation in numbers and composition in an ecologically dynamic ecotonal region in response to multiyear changes in precipitation.     

Food habits and nest characteristics of breeding raptors in southwestern Wyoming

Food habits and nest site features of the Golden Eagle ( Aquila chrysaetos ), Prairie Falcon ( Falco mexicanus ), Red-tailed Hawk ( Buteo jamaicensis ), and Ferruginous Hawk ( B. regalis ) were studied near Medicine Bow, Wyoming, during 1981 and 1982. Foods consisted primarily of leporids and sciurids. The Wyoming ground squirrel ( Spemiophilus richardsonii ) dominated the diet of Prairie Falcons, while Golden Eagles preyed on leporids more than did the other raptors. Diet overlap ranged from 59 to 99% between the species. Mean height of Golden Eagle nests was greater than nest height of other species. Most raptor nests (78%) were not visible from other active nests and were in view of roads. Prairie Falcons were the most specialized and Ferruginous Hawks the most versatile raptor species in terms of food habits and use of nest sites.     

Vertebrate fauna of the Idaho National Environmental Research Park

The relative abundance, habitat use, and seasonal occurrence are reported for the 6 fish, 1 amphibian, 9 reptile, 164 bird, and 39 mammal species recorded on the Idaho National Environmental Research Park in southeastern Idaho.     

Small-stone content of Mima mounds of the Columbia Plateau and Rocky Mountain regions: implications for mound origin

Mima moundfields were investigated at the Lawrence Memorial Grassland Preserve, located on the Columbia Plateau in southern Wasco County, Oregon, and at three locations in the San Luis Valley and Sangre de Cristo Mountains, southern Colorado, to test the alternative hypotheses of mound origins by erosion, frost action, and soil translocation by geomyid pocket gophers. The concentrations of two size classes of small stones, gravel (8-15 mm diameter) and pebbles (15-50 mm diameter), were sampled along mound-to-intermound transects and at different depths within the mounds. Numbers and masses of small stones per unit soil volume increased from intermounds to mounds tops at the Colorado sites and from mound edge to mound top at the Oregon site, where thin intermound soils lay directly on the weathering surface of basalt bedrock. Numbers and masses of small stones in the surface soil of mound tops were greater than or similar to concentrations in deeper layers. Mean masses of individual pebbles were greater in the intermound zone than in mound soils at the Oregon site, but did not differ along mound-intermound gradient at the Oregon site and at one Colorado site, being highest at mound edges or in intermounds. These observations support the hypothesis that mounds are formed by centripetal translocation of soil by geomyid pocket gophers, and are contrary to predictions based on theories assuming erosion or frost action to be the mechanism of mound formation.     

Observations of captive Rocky Mountain mule deer behavior

Observations were made on the behavior of a captive herd of Rocky Mountain mule deer ( Odocoileus hemionus hemionus ). Comparisons in general behavior patterns were made between captive and wild deer. Similar behavior was exhibited by captive and wild deer. Captive deer (as well as other species) may be useful for study of certain behavioral aspects of their wild counterparts.     

Alkaloidal relationships in the genus Arctomecon (Papaveraceae) and herbivory in A. humilis

The previously reported alkaloids (including protopines, benzophenanthridines, tetrahydrobenzylisoquinolines, and protoberberines) of the genus Arctomecon (Papaveraceae) are discussed in relation to their distribution in the plant kingdom, in the Papaveraceae, and among the three species of Arctomecon . The biological activity of these alkaloids is discussed, and possible implications for herbivore and plant-insect interactions in A. humilis are presented.